Igniter compositions



use,

KGNHTER COMPOSITIONS No Drawing. Application December 31, 1952, Serial No. 329,111

2 Claims. (Ci. 522) This invention relates to igniter compositions for tracer projectiles, and contemplates an igniter that will bur: and perform its function of igniting the actual tracer composition with little if any flame or light.

Tracer projectiles are particularly useful for the firing of aircraft guns and perform the function of indicating the direction of tire of a gun on a somewhat unstable mount with respect to a target usually having a high speed of movement relative to the gun. It is essential that the trace be clearly visible to the gunner or observer in the region of the target, but the flash of light immediately adjacent the muzzle of the gun has an adverse effect on the shooters vision and his ability to accurately observe the trace in the region Where the trace is of significance.

The present invention contemplates an igniter composition which leaves an invisible or dim trace to a minimum distance of twenty-five (25) yards and a bright and properly colored trace at greater distances.

Conventional igniter compositions comprise a very active fuel, such as powdered magnesium, tempered with a less energetic fuel, such as calcium resinate, and 2.;- active oxidizer and coloring agent which may be an admixture of such reagents as the peroxides of barium, strontium and lead. Igniters of this type burn immediately with a very luminous flame with an undesirable blinding of the observer by the bright trace at the shortv ranges where the trace is of little if any value.

It has been found that igniter compositions which include a fuel of the type of calcium silicide, as a partial or entire replacement for a fuel of the type of magnesium, burn in such a manner that the trace for a minimum distance of twenty-five (25) yards is only dimly visible if visible at all. Notwithstanding this, these compositions effectively perform their intended function of igniting the actual tracer composition at a range of twenty-five (25) to seventy-five (75) yards, the com-- "ice bustion of the tracer composition thereafter furnishing a trace of the desired color, intensity and duration.

Typical igniter compositions according to the invention are as follows:

Range, Preferred.

Percent Percent;

Strontium Peroxide 75. 0-81.0 78 Barium Peroxide 3. 9- 4.1 4 Lead Per0x1de 3. 9- 4.1 4 Calcium Resinate 6. 0- 8.0 7 Calcium Silicide 3. 0-11. 0 7

Per cent Strontium peroxide 75.0-81.0 Barium peroxide 3.9- 4.1 Lead peroxide 3.9- 4.1 Calcium resinate 6.0- 8.0

Calcium silicide 3.011.0

2. An igniter for tracer compositions consisting essentially of-- Per cent Strontium peroxide 78 Barium peroxide 4 Lead Peroxide 4 Calcium resinate 7 Calcium silicide 7 References Cited in the file of this patent UNITED STATES PATENTS 1,708,187 Meek Apr. 9, 1929 1,756,255 Meek Apr. 29, 1930 1,903,814 Grafi Apr. 18, 1933 2,115,047 Stevenson Apr. 26, 1938 2,115,608 Brandt Apr. 26, 1938 2,410,801 Audrieth Nov. 12, 1946 FOREIGN PATENTS 275,021 Great Britain Aug. 4, 1927 

1. AN IGNITER FOR TRACER COMPOSITIONS CONSISTING ESSENTIALLY OF- 